Formulations for oral delivery of various pharmaceutically-active compounds, particularly unpalatable ones such as aspirin, ibuprofen, cimetidine, acetaminophen, erythromycin, or the like, are well known in the art. Generally, unacceptable taste characteristics due to acidity, bitterness, burning in the back of the throat, or odorousness, have been overcome, by coatings, capsules, flavoring agents or combinations of these features. See for example, formulations which are intended to be swallowed whole, such as those disclosed in U.S. Pat. No. 4,726,966, which coats granular ibuprofen with an acrylic acid resin in the presence of an organic solvent and water; U.S. Pat. No. 4,835,186, which discloses spray-drying ibuprofen in a suspension of colloidal silica, alcohol, and cellulose acetate; and U.S. Pat. No. 4,916,161, which discloses coating ibuprofen via a wet granulation method using certain methyl cellulose phthalates as taste-masking agents. Each of these formulations, however, has been devised in order to momentarily disguise or prevent these objectionable features while the compound is passing through the mouth and throat and being swallowed without being masticated.
U.S. Pat. No. 4,755,387 employs lipids to coat therapeutic agents such as aspirin in order to assure slow absorption in the stomach. Alternative timed-release aspirin formulations are disclosed in U.S. Pat. No. 4,375,468, employing such slow-release coating agents as waxes, fats, cellulose esters, etc., alone or in various combinations. This patent claims a slow-release formulation comprising aspirin, hydrogenated vegetable oils, and saccharides prepared in an organic solvent solution. Similarly, U.S. Pat. No. 4,761,407 discloses a formulation for oral administration of various active agents which are first dissolved in a heated liquid organic phase, followed by mixing this liquid with a second, different organic phase, and cooling this liquid to a solid dosage form.
Unfortunately, for certain classes of ill persons, or even in veterinary applications, swallowing of a tablet or capsule containing these unpalatable compounds is difficult or impossible; this is particularly so in the very elderly or in young children. This situation leads to problems with noncompliance in maintaining the dosage schedules for the patients. Moreover, many such formulations, as evidenced by the cited art, are very complex in their composition or preparation or both, and thus costly and difficult to make. See, for example, the chewable formulation disclosed In U.S. Pat. No. 4,882,152 comprising an active ingredient pre-coated with glycerides, lecithin, polyoxyalkylenes, or polyalkylene glycols, and mixed into a binder comprising a gelatin, a sweetener, glycerin, and water.
A relatively simple formulation, especially of such unpalatable drugs as aspirin, ibuprofen, cimetidine, acetaminophen, erythromycin, or the like which could readily be chewed before swallowing without suffering the bitterness, burning, or unpleasant taste or odor of these unpalatable compounds would be highly desirable.